The present invention is directed to the field of safety systems which may, for example, be used with industrial vehicles such as forklift trucks. More particularly, the present invention is directed to a safety system for sensing and responding to the existence of a potentially dangerous situation to reduce the occurrence of accidents.
Industrial assembly and merchandising plants employ a large number of industrial vehicles, typically forklift trucks, and experience an inordinate amount of lost time accidents resulting from pedestrian-vehicle accidents. The vehicle operator will often have a large load s/he is coping with and necessarily has her/his full attention on avoiding various obstacles in the vehicle""s path. The pedestrians, on the other hand, will frequently enter a region where a forklift truck is operating and be unaware of the potential danger posed thereby. Finally, one or more pedestrians may be in conversation with the forklift operator when the industrial truck is stopped. Believing the conversation to be over, the operator may begin moving the vehicle being unaware that one of the pedestrians is in contact with the vehicle or has an appendage in the path of the truck.
A number of previous attempts have been made to deal with this problem. Many of these systems lack the flexibility required to adapt to various operational situations. Other systems are overly sensitive, picking up inanimate articles near the path of the vehicle resulting in false alarms sometimes requiring the operator to override the safety system to resume normal operation. Other systems fail to distinguish between a pedestrian that is safely passing the vehicle and one that is entering a potentially dangerous situation.
It is a feature of the present invention to deal effectively with this safety problem significantly reducing the incidence of pedestrian-vehicle accidents while overcoming the short comings of the prior art systems. The vehicle safety system of the present invention is for use with an industrial vehicle such as a forklift truck and includes sensor means for detecting at least one person in a particular zone; receiver means associated with said sensor means for producing a response to a detection of an object in said particular zone, said response selected from the group consisting of disabling the industrial vehicle from moving and sounding a warning signal. The sensor means comprises a sensor mounted on the vehicle, or in a zone where the industrial vehicle is operating, for detecting at least one person in a particular zone.
The particular zone comprises a first zone proximate the industrial vehicle and the response consists of disabling the industrial vehicle from moving. The sensor for this first zone will be activated when the vehicle is stopped and will be deactivated when the vehicle begins moving. The particular zone may alternatively be (or in addition include) a second zone adjacent side portions and said response consists of sounding a warning signal, possibly using the industrial vehicle""s horn. The sensor means detects a direction of motion of the person entering said second zone and only activates said warning signal if the person is at risk to walk into the side of the industrial vehicle or into the path of the vehicle. The sensors for the second and subsequent zones will be activated when the sensor for the first zone is deactivated, i.e., when the vehicle is moving. The sensor means may be selected from the group consisting of infrared, ultrasonic, radio frequency, laser, electromagnetic, microwave, Doppler shift, photoelectric and motion detection. The sensor means preferably has adjustable sensitivity, range and focus area. It is desirable for some applications that the sensor be capable of distinguishing between animate and inanimate objects but such capability is not essential for the operation of the system.
The particular zone may include a third zone which comprises an area defined as at least one visually obstructed region where the industrial vehicle operates and said response consists of sounding a warning signal, perhaps using the industrial vehicle""s horn. In addition, the system may give the vehicle operator a visual signal by illuminating a light on the vehicle""s control panel. In the third zone the sensor means preferably comprises one or more motion detectors proximate hidden xe2x80x9cdanger zonesxe2x80x9d, i.e., those regions where personnel may enter through a door or around a corner and be unaware that an industrial truck is operating in the area. In zone three, the motion detector will preferably activate an RF tag enclosed within the sensor. If an industrial vehicle is operating in the area, an RF transceiver on the vehicle will receive a reflected signal from the RF tag and the horn will sound to give the pedestrian, as well as the driver, a xe2x80x9cheads upxe2x80x9d that a forklift truck and a pedestrian are operating in the same region.
The invention contemplates a multiple-zone safety system for use with an industrial vehicle, in which the multiple-zone safety system includes at least one (and preferably two) of a) a first zone proximate the industrial vehicle; b) a second zone adjacent side portions of the industrial vehicle; c) a third zone defined as at least one visually obstructed region where the industrial vehicle operates; the safety system including i) a sensor means for each of said zones included in the system; ii) receiver means associated with all of the sensor means to provide a response appropriate to the sensor means for each of the zones.
The invention also contemplates a process of establishing a multiple-zone safety system for an industrial vehicle comprising the steps of sensing at least two of a) a person in a first zone proximate the industrial vehicle; b) a person in a second zone adjacent side portions of the vehicle; c) a person in a third zone which includes at least one visually obstructed region in which the industrial vehicle operates; and d) providing a receiver means associated with said sensor means for producing a response to a detection of an animate object in said particular zone, the response selected from the group consisting of disabling the industrial vehicle and sounding a warning signal.
Various other features advantages and characteristics will become apparent after a reading of the following specification.